Graphene oxide (GO) doping and reduction allow for physicochemical property modification to suit practical application needs. Herein, the challenge of simultaneous low-thermal-budget heteroatom doping of GO and its reduction in ambient air is addressed through the synthesis of B-doped reduced GO (B@rGO) by flash irradiation of boric acid loaded onto a GO support with intense pulsed light (IPL). The effects of light power and number of shots on the in-depth sequential doping and reduction mechanisms are investigated by ex situ X-ray photoelectron spectroscopy and direct millisecond-scale temperature measurements (temperature >1600 degrees C, < 10-millisecond duration, ramping rate of 5.3 x 10(5) degrees C s(-1)). Single-flash IPL allows the large-scale synthesis of substantially doped B@rGO (approximate to 3.60 at% B) to be realized with a thermal budget 10(6)-fold lower than that of conventional thermal methods, and the prepared material with abundant B active sites is employed for highly sensitive and selective room-temperature NO2 sensing. Thus, this work showcases the great potential of optical annealing for millisecond-scale ultrafast reduction and heteroatom doping of GO in ambient air, which allows the tuning of multiple physicochemical GO properties.